Auricular transverse muscle shortening as an adjunct to perichondrium-sparing Mustarde otoplasty

Anuran jumping is one of the most powerful accelerations in vertebrate locomotion. Several species are hypothesized to use a catapult-like mechanism to store and rapidly release elastic energy, producing power outputs far beyond the capability of muscle. Most evidence for this mechanism comes from measurements of whole-body power output; the decoupling of joint motion and muscle shortening expected in a catapult-like mechanism has not been demonstrated. We used high-speed marker-based biplanar X-ray cinefluoroscopy to quantify plantaris muscle fascicle strain and ankle joint motion in frogs in order to test for two hallmarks of a catapult mechanism: (i) shortening of fascicles prior to joint movement (during tendon stretch), and (ii) rapid joint movement during the jump without rapid muscle-shortening (during tendon recoil). During all jumps, muscle fascicles shortened by an average of 7.8 per cent (54% of total strain) prior to joint movement, stretching the tendon. The subsequent period of initial joint movement and high joint angular acceleration occurred with minimal muscle fascicle length change, consistent with the recoil of the elastic tendon. These data support the plantaris longus tendon as a site of elastic energy storage during frog jumping, and demonstrate that catapult mechanisms may be employed even in sub-maximal jumps.

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The energetics of frog rectus abdominis muscle shortening under isotonic load

Cellular and Molecular Life Sciences ◽

10.1007/bf01965297 ◽

1972 ◽

Vol 28 (11) ◽

pp. 1285-1286 ◽

Cited By ~ 1

Author(s):

R. A. Chaplain

Keyword(s):

Rectus Abdominis ◽

Rectus Abdominis Muscle ◽

Muscle Shortening

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Force depression following skeletal muscle shortening is long lasting

Journal of Biomechanics ◽

10.1016/s0021-9290(98)00126-2 ◽

1998 ◽

Vol 31 (12) ◽

pp. 1163-1168 ◽

Cited By ~ 33

Author(s):

W. Herzog ◽

T.R. Leonard ◽

J.Z. Wu

Keyword(s):

Skeletal Muscle ◽

Force Depression ◽

Muscle Shortening

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Comparison of Biomechanical and Anatomical Effects Following Eccentric and Concentric Exertions

Proceedings of the Human Factors and Ergonomics Society Annual Meeting ◽

10.1177/154193120504901405 ◽

2005 ◽

Vol 49 (14) ◽

pp. 1287-1291

Author(s):

Amrish O. Chourasia ◽

Mary E. Sesto ◽

Youngkyoo Jung ◽

Robert S. Howery ◽

Robert G. Radwin

Keyword(s):

Signal Intensity ◽

Intensity Ratio ◽

Maximum Voluntary Contraction ◽

Magnetic Resonance Images ◽

Voluntary Contraction ◽

Work Place ◽

Signal Intensity Ratio ◽

Mechanical Stiffness ◽

Average Decrease ◽

Muscle Shortening

Work place exertions may include muscle shortening (concentric) or muscle lengthening (eccentric) contractions. This study investigates the upper limb mechanical properties and magnetic resonance images (MRI) of the involved muscles following submaximal eccentric and concentric exertions. Twelve participants were randomly assigned to perform at 30° per second eccentric or concentric forearm supination exertions at 50% isometric maximum voluntary contraction (MVC) for 30 minutes. Measurement of mechanical stiffness, isometric MVC, localized discomfort and MRI supinator: extensor signal intensity ratio was done before, immediately after, 1 hour after and 24 hours after the bout of exercise. A 53% average decrease in mechanical stiffness after 1 hour was observed for the eccentric group (p< 0.05) compared to a 1% average decrease for the concentric group (p> 0.05). Edema, indicative of swelling, was observed 24 hrs after exercise, with an average increase in the MRI supinator: extensor signal intensity ratio of 36% for the eccentric group and less than 10% for the concentric group (p<0.05).

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Antagonist cocontraction of knee flexors during constant velocity muscle shortening and lengthening

Journal of Electromyography and Kinesiology ◽

10.1016/1050-6411(93)90002-e ◽

1993 ◽

Vol 3 (2) ◽

pp. 78-86 ◽

Cited By ~ 11

Author(s):

Christopher J. Snow ◽

Juliette Cooper ◽

Arthur O. Quanbury ◽

Judy E. Anderson

Keyword(s):

Constant Velocity ◽

Muscle Shortening ◽

Knee Flexors

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Muscle dynamics in skipjack tuna: timing of red muscle shortening in relation to activation and body curvature during steady swimming

Journal of Experimental Biology ◽

10.1242/jeb.202.16.2139 ◽

1999 ◽

Vol 202 (16) ◽

pp. 2139-2150 ◽

Cited By ~ 18

Author(s):

R.E. Shadwick ◽

S.L. Katz ◽

K.E. Korsmeyer ◽

T. Knower ◽

J.W. Covell

Keyword(s):

Fork Length ◽

Muscle Length ◽

The Body ◽

Emg Activity ◽

Skipjack Tuna ◽

Force Transmission ◽

Muscle Strain ◽

Muscle Shortening ◽

Red Muscle ◽

Length Changes

Cyclic length changes in the internal red muscle of skipjack tuna (Katsuwonus pelamis) were measured using sonomicrometry while the fish swam in a water tunnel at steady speeds of 1.1-2.3 L s(−)(1), where L is fork length. These data were coupled with simultaneous electromyographic (EMG) recordings. The onset of EMG activity occurred at virtually the same phase of the strain cycle for muscle at axial locations between approximately 0.4L and 0.74L, where the majority of the internal red muscle is located. Furthermore, EMG activity always began during muscle lengthening, 40–50 prior to peak length, suggesting that force enhancement by stretching and net positive work probably occur in red muscle all along the body. Our results support the idea that positive contractile power is derived from all the aerobic swimming muscle in tunas, while force transmission is provided primarily by connective tissue structures, such as skin and tendons, rather than by muscles performing negative work. We also compared measured muscle length changes with midline curvature (as a potential index of muscle strain) calculated from synchronised video image analysis. Unlike contraction of the superficial red muscle in other fish, the shortening of internal red muscle in skipjack tuna substantially lags behind changes in the local midline curvature. The temporal separation of red muscle shortening and local curvature is so pronounced that, in the mid-body region, muscle shortening at each location is synchronous with midline curvature at locations that are 7–8 cm (i.e. 8–10 vertebral segments) more posterior. These results suggest that contraction of the internal red muscle causes deformation of the body at more posterior locations, rather than locally. This situation represents a unique departure from the model of a homogeneous bending beam, which describes red muscle strain in other fish during steady swimming, but is consistent with the idea that tunas produce thrust by motion of the caudal fin rather than by undulation of segments along the body.

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Shortening deactivation: quantifying a critical component of cyclical muscle contraction

AJP Cell Physiology ◽

10.1152/ajpcell.00281.2021 ◽

2021 ◽

Author(s):

Amy K. Loya ◽

Sarah K. Van Houten ◽

Bernadette M. Glasheen ◽

Douglas M. Swank

Keyword(s):

Power Output ◽

Muscle Activation ◽

Muscle Relaxation ◽

Length Change ◽

Isometric Tension ◽

Energetic Cost ◽

Muscle Shortening ◽

Shortening Deactivation ◽

Muscle Types ◽

Flight Muscles

A muscle undergoing cyclical contractions requires fast and efficient muscle activation and relaxation to generate high power with relatively low energetic cost. To enhance activation and increase force levels during shortening, some muscle types have evolved stretch activation (SA), a delayed increased in force following rapid muscle lengthening. SA's complementary phenomenon is shortening deactivation (SD), a delayed decrease in force following muscle shortening. SD increases muscle relaxation, which decreases resistance to subsequent muscle lengthening. While it might be just as important to cyclical power output, SD has received less investigation than SA. To enable mechanistic investigations into SD and quantitatively compare it to SA, we developed a protocol to elicit SA and SD from Drosophila and Lethocerus indirect flight muscles (IFM) and Drosophila jump muscle. When normalized to isometric tension, Drosophila IFM exhibited a 118% SD tension decrease, Lethocerus IFM dropped by 97%, and Drosophila jump muscle decreased by 37%. The same order was found for normalized SA tension: Drosophila IFM increased by 233%, Lethocerus IFM by 76%, and Drosophila jump muscle by only 11%. SD occurred slightly earlier than SA, relative to the respective length change, for both IFMs; but SD was exceedingly earlier than SA for jump muscle. Our results suggest SA and SD evolved to enable highly efficient IFM cyclical power generation and may be caused by the same mechanism. However, jump muscle SA and SD mechanisms are likely different, and may have evolved for a role other than to increase the power output of cyclical contractions.

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